1) Does the 2nd gen patch also work on the 15 generation IV PKMN from Brown so you could have the total of 266 Pokémon?
2) If we need to re-patch, can you patch it again with the pre-patched rom or do I patch a fresher Red Version?
1. No, basically it reverts to its previously evolved form, but it has the same stats and moves.
2. Repatch it to a clean Red ROM and rename it.